So basically all laptops that have discrete graphics have it socketed in an nVidia MXM slot. Way cheaper to have one board and just knock cards on it for the manufacturers. However the thing is that since it is for OEMs and not consumers, it isn't as easy to swap as a PCI card. It is all on you to make sure the card you are getting is physically the right size, electrically something you system can handle, and thermally not to much.

Also pretty much only Sager actually supports doing it, and other laptop manufacturer will tell you to GTFO if you ask them about it. As such even finding the parts isn't easy.

With laptops you don't really upgrade much other than maybe the RAM or disk.

However the IB will be useful in laptops not only because it can give better performance for integrated only systems, but it'll be nice for switchable ones. You can get ATi card systems where you can manually switch between discrete and integrated and nVidia ones that do it on the fly. Better integrated graphics means you can use them for more things, so when on battery it is more feasible to use them and leave the discrete system shut down.

However note this wasn't a laptop part they are talking about, this is the desktop part.

Look at the die layout [pcper.com] for Sandy Bridge, there's no Ivy Bridge layout yet but it's probably the same. You see that huge chunk called "graphics"? Me neither, it's somewhere in those small "misc io" bits. That's the only little thing of your CPU you aren't using with a dGPU.

There have been a few stabs at it, I think both ATI and Nvidia have released more-or-less-orphaned-on-launch partnerships with some laptop outfit or other, using proprietary cabling.

My understanding is that there are a few major hurdles:

Historically, there really haven't been any good standardized high-bandwidth interfaces to the outside world on laptops. The proprietary docking station port, if provided, might connect directly to the PCI bus; but your next best bets were relatively lousy things like PCMCIA or USB. Even with PCIe, you get 1x from an expresscard slot; but the standards for external cabling for anything beefier than that have been languishing in the PCIe SIG forever...

Unless you are content to use an external monitor only, an 'expansion GPU' both has to have access to all the usual bandwidth that a GPU requires and have enough bandwidth(and suitable software/firmware cooperation) to dump its framebuffer back to whatever internal GPU is driving the laptop screen. You can get(albeit at unattractive prices) enclosures that connect to the 1xPCIe lane in an expresscard slot and break that out into a mechanically 16xPCIe card enclosure with supplemental power. Assuming the BIOS isn't a clusterfuck, you can pop in an expansion card just as you would on a desktop. That only gets you the video outs, though, it doesn't solve the trickier and more system-specific problem of driving the laptop screen.

Docking stations: At present, laptop manufacturers get to designate one line as 'enterprise' by including the necessary connector, and then charge a stiff fee for the proprietary docking station as your only option to drive a few extra heads. I imagine that this blunts the enthusiasm of the major enterprise laptop players for a well-standardized and high bandwidth external connector.